The invention relates to a device for generating milk froth as well as a method for generating milk froth.
Due to the popularity of coffee-milk mixed drinks, devices for frothing milk are increasingly in use. Here, particularly in the restaurant field, high requirements are set for the quality of the froth generated. Several methods are known to generate milk froth:
A milk container that can be heated is known from EP 0 626 148 A1, comprising a resistance valve for frothing milk. The resistance valve comprises a rod-shaped element and a lamellae-like structure provided at its perimeter, which forms a labyrinth-like passage, with the milk being pressed through it. At the circumference of the rod-shaped element annular lamellae with unevenly distributed recesses are inserted at a regular distance from each other. By the resistance valve a repeated acceleration and deceleration of the milk-air mixture occurs, thus a repeated increase and reduction in pressure, as well as a turbulent mixing.
It is known from EP 0 485 350 A1 to generate warm milk froth by way of conveying milk via a pump from a reservoir, introducing air thereto, and subsequently, if necessary, heating the milk froth in a continuous-flow heater. In the outlet line, downstream in reference to the pump, a reduction of the cross-section is found, which leads to an increase in pressure. The reduction in cross-section is yielded by a rod-shaped element arranged in the outlet line, which can extend to the continuous-flow heater.
From WO 2008/083941 A1 it is known to convey milk via a pump to a throttle, and subsequently to convey the milk froth optionally directly to an outlet for dispensing cold milk froth or via a continuous-flow heater to an outlet for dispensing warm milk froth.
From EP 2 298 142 A1 it is known to increase the quality of the milk froth by using an intermittent air valve.
In the latter-most device mentioned the increase in pressure occurs by a throttle. A throttle or a throttle site is formed by a reduction in cross-section and perhaps a subsequent expansion in cross-section in the outlet pipe, downstream in reference to the pump.